Inductive angle-of-rotation sensors are used, for example, in rotary transducers to determine the angular position of two machine parts that are rotatable relatively to one another. In inductive angle-of-rotation sensors, excitation coils and receiving coils, for instance, in the form of printed conductors, are applied to a shared printed-circuit board, which is permanently connected, for example, to a stator of a rotary transducer. Disposed oppositely to this printed-circuit board is another board, e.g., in the form of a graduated disk, on which electrically conductive and non-conductive surfaces are applied so as to alternate in regular intervals, forming a graduation region or graduation structure, and which is connected in a torsionally fixed manner to the rotor of the rotary transducer. When an electric excitation field, alternating with respect to time, is applied to the excitation coils, signals are generated in the receiving coils as a function of the angular position during the relative rotation between the rotor and stator. These signals are then processed further in an evaluation electronics. Typically, the components of such an evaluation electronics are accommodated on another printed-circuit board.
Rotary transducers having inductive angle-of-rotation sensors are used as measuring devices for electrical drives, to determine the absolute angular position of corresponding drive shafts. In many fields of application of such angle-of-rotation sensors or rotary encoders, the need has existed for some time to miniaturize these devices.
German Published Patent Application No. 197 51 853 of the Applicant hereof describes a design for an inductive angle-of-rotation sensor, where the excitation and receiving coils are configured in a multi-layer printed-circuit board structure. When reducing the size of such an angle-of-rotation sensor, particularly when reducing the diameter of the scanning circuit board, it becomes evident that the receiving printed conductors, in particular, which supply signals having one signal period over one rotation, produce an intolerable offset error.
It is an aspect of the present invention to provide an inductive angle-of-rotation sensor, which may allow an excellent signal quality to be attained, even when working with the smallest sizes. An aspect of the present invention may also provide a reliable rotary transducer having small outer dimensions.